Injection system for electric device



Jan. 19, 1965 H. LEBOUTET 3,166,477

INJECTION SYSTEM FOR ELECTRIC DEVICE Filed Dec. '1, 1959 4 Sheets-Sheet 1 Fig.1

INVE.NTOR H. LEBOUTET BY G7m Jan. 19, 1965 H. LEBOUTET INJECTION SYSTEM FOR ELECTRIC DEVICE- 4 Sheets-Sheet' 2 Filed Dec. '7, 1959 INVENTOR H. LEBOUTET BY w? ATTORNEY Jan. 19, 1965 H. LEBOUTET 3,166,477

INJECTION SYSTEM FGR ELECTRIC DEVICE Filed Dec. '7, 1959 4 Sheets-Sheet 3 p oooooooooo INVENTOR H. LEBOUTET Jan. 19, 1965 H. LEBOUTET 3,166,477

INJECTION SYSTEM FOR ELECTRIC DEVICE Filed Dec. 7, 1959 4 Sheets-Sheet 4 a DO 0C 00 14 6 Pi. 3e

INVENTOR H. LEBOUTET United States Patent OfiiCt? 3,166,477 INJECTION SYSTEM FGR ELECTRIC DEVICE Hubert Leboutet, Paris, France, assignor to Compagnie Generale de Teiegraphie Sans Fil, Paris, France Filed Dec. 7, 1959, Ser. No. 857,831 Claims priority, application France Dec. 24, 1958 4 Claims. (Cl. 1765) The present invention relates to devices in which the plasma, that is, an electrically neutral gas constituted by a mixture of ions and electrons, is compressed with a view to carry the same at a relatively high kinetic temperature that may eventually lead to a reaction of thermonuclear fusion.

More particular, the-present invention relates to the type of devices having so-called magnetic mirrors, i.e., to the device constituted generally by an evacuated vessel or enclosure having two distinct extremities in which is produced a longitudinal magnetic field intermediate these two extremities, this magnetic field being uniform except within the regions adjacent the extremities where the lines offorce are compressed or constricted. This region of compressing or constriction of the magnetic field constitutes a magnetic mirror which reflects the charged particles moving in the direction toward the magnetic mirror regardless of the sign thereof. The totality of the lines of force of the longitudinal field together with the constrictions at the extremities thereof effectively define a so-called magnetic bottle which surrounds or envelops the plasma andwhich compresses the same while at the same time confining the plasma within a region of the space insulated from the walls of the vessel or enclosure.

In View of the inevitable losses of the particles across the walls or the extremities of the magnetic bottle as well as in view of the necessity to evacuate the burnt-up particles and to replace the same by fresh particles, it is necessary to inject periodically fresh plasma into the vessel in such a manner that the plasma is retained at the interior of the magnetic bottle.

, Consequently, there arises the problem of a practical realization of an injection system in such a manner that the plasma may enter into the magnetic bottle at the moment of injection but that the bottle is closed as tightly as possible beween injection periods.

There is known an injection system in the prior art un der the designation of DCX (see Project Sherwood, by AS. Bishop, 1958, page 136), which system is based on the projection across the walls ofthe bottle of a beam of molecular ions having a high energy which dissociate themselves at least in part along an arc establishedat the interior. of the bottle into atomic ions of which the mass is two times less. These ions turn about lines of force of the magnetic field of the bottle along trajectories which remain at the interior of the zone of confinement,

whereas the molecular ions of double mass return toward the source.

One inconvenience and shortcoming of this prior art system is the fact that the arc within the zone of confine 'ment determines a cold region with respect to the high temperatures under consideration, and the plasma as a 'result thereof is cooled off by the effect of this zone to such a point that the possibility of obtaining the desired high temperatures may be impaired.

Accordingly, it is a main object of the present invention to provide a new and improved injection system for the 3,156,477 Patented Jan. 19, 1965 in the provision of an injection system for plasma which is simple in construction, readily controllable, yet effective and reliable in operation.

A still further object of the present invention resides in the provision of an injection system for plasma normally confined within a magnetic field of bottle-shape configuration in which the bottle of the magnetic field is effectively opened only temporarily to admit fresh plasma,

These and other objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawing which shows, for purposes of illustration only, one embodiment in accordance with the present invention, and wherein:

FIGURE 1 is a longitudinal cross-sectional view of an injection system in accordance with the present invention;

FIGURE 2 is a diagram indicating the respective posi- -tion of the control pulses along the time basis, and

FIGURES 3a to 3;; illustrate a series of schematic views of the arrangement of FIGURE 1, illustrating the different stages during a cycle of operation thereof.

According to the present invention, the chamber for the production of high kinetic temperature is in communication with an injection chamber, the passage of particles from one chamber to the other chamber between injections being effectively prevented by 'a magnetic mirror having a controlled opening thereof at the moment of the injection and thereby operating as a so-called magnetic shutter. Prior to opening of the magnetic shutter, the plasma is injected into the injection chamber where it is confined and compressed in a second magnetic bottle which is clo ed on one side thereof by the shutter in question and on the other by a movable magnetic mirror operating in the manner of a magnetic piston which pushes or displaces the plasma toward the shutter.

Referring now to the drawing, wherein like reference numerals are used throughout the various views to designate corresponding parts, and more particularly to FIG- URE 1, which is a longitudinal cross-sectional view of an injection system according to the present invention, reference numeral 1 design-ates a cylindrical element, for example, of Pyrex in which are produced the high temperatures of the plasma. The necessary vacuum is continuously maintained within the cylinder 1 bymeans of the vacuum pump 2 which may be'of any suitable construction. Several magnetic coils or windings are disposed about cylinder 1, namely as follows:

A first coil assembly 3 is provided which is intended to produce the magnetic field of correct form for confining and stabilizing the plasma within the cylinder 1. An auxiliary coil 4 is provided at the left end of the cylinder 1, as viewed in FIGURE 1, which is intended to produce a magnetic mirror within the region of the left end or extremity of the cylinder 1. A coil 5 is disposed the production of the high temperatures. All of the coilsdescribed so far hereinabove are supplied continuously from suitable electric current sources, not illustrated in the drawing.

An auxiliary winding 6, wound in the opposite direction with respect to coil 5 is disposed along the inside of the latter. The auxiliary winding 6 is supplied from a controlled current source 7 which, when controlled by a control pulse, as will be explained more fully hereinafter, transmits to the Winding 6 a current pulse of such intensity that the magnetic action of the winding 5 is momentarily annulled.

The portion of the cylinder 1 between the region of the in coil and the right extremity of cylinder 1 constitutes the injection chamber. The injection chamber portion of cylinder 1 is surrounded by a coil assembly 8 analogous to that of the coil assembly 3, which is also supplied continuously from a suitable current source, not illustrated in the drawing, and which serves the purpose of creating the magnetic confining field within the injection chamber. An auxiliary winding 9 is disposed on the inside of the coil assembly 8 of which the turns are periodically connected to' one side of shunt condensers 10, the other side of which are each connected to ground. The totality of coil portions 9 and condensers It) in effect constitute a delay line having predetermined delay characteristics, as is well known in the art. Adjacent the winding 5, the delay line Y 9, 10 is terminated by a matched resistance or impedance 1 11. On the opposite end, the delay line 9, 10 is connected to a control current source 12 which, when controlled by a control pulse, as will be described more fully. hereinafter, sendsra current pulse along the delay line 9,161

An ion fun 13 andan electron gun 14 of conventional construction extend into the right extremity of the injection chamber. It is understood that the ion and electron guns, illustrated schematically by blocks 13 and 14-, are, in fact, of any known structure which include all of the necessary electrodes, power supplies, and gas supply sources such as, for instance, deuterium for the ion gun. The ion gun 13 and the electron gun 14 as well as the necessary parts thereof thus constitute effectively the plasma injection means of the system. The control electrodes of the guns 13 and 14 are connected-to the terminal a of a which transmits or applies the control pulses through the intermediary of the distributor 15, at

the proper timed moments, to the terminals a, b and c. 7

Operation longitudinal magnetic lines of force 17,whereas the wind-,'

ings 4 and 5 produce respectively the constrictions 18 and 19 of the lines of force forming the so-called magnetic mirrors. The totality of the lines of force '17, 13 and 19 form so-called magnetic bottle. The winding 8 produces the lines of force 20 such-that the totality of the lines of force 19, 2% forms within the injection chamber a magnetic bottle closed at 19 but open at the opposite end thereof.

At the moment z (FIGURE 2), the arm of the distributor 15 is effectively in contact with the terminal a, and a control pulse 21 is transmitted from the source 16 to the control electrodes of the guns 13 and 14. As a result thereof, the gun 13 injects into the injection chamber a cloud of ion gas, for example, deuterons, whereas the gun 14 injects an essentially equal quanti-ty'of free electrons. The injection may take place at a relatively high energy level, for example, of the order of 100 kev. The ions and electrons intermingle and form the plasma 22 (FIG- URE 3b). 1

At the moment t approximately at which terminates the pulse 21 (FIGURE 2), the arm of the distributor 15 passes over to the terminal b, and as a result thereof, a control pulse is transmitted to the source 12 which sends a pulse 23 (FIGURE 2) to the winding 9. At this moment (FIGURE the magnetic field within the may be readily seen that the magnetic bottle defined by the constrictions 19 and 24 becomes shorter and shorter and that the constriction 24-in eifect acts in-the manner of a magnetic piston, pushing the plasma 22 toward the chamber 'for the production of high temperatures and compressing the samewithin' the magnetic bottle intermediate the constricted portions 19 and 24.

FIGURE 3e corresponds tothe moment 1 at which the pulse 23 has arrived at the left end of the delay line 9, 10',

and is absorbed by the resistance 11. Consequently, the

pulse at r, is illustrated in FIGURE 2-in dash lines and designated therein by reference numeral23. The plasma 22 is at the same time compressed to the maximum between the constrictions 19 and 24 and the latter constriction 24 is at that time in is end position. I I

At this moment, the armof the distributor 15 passes over the terminal 0. a control pulse to the current source 7 which, in turn, sends a pulse 25 (FIGURE 2) to the winding 6. The field of the coil 5 is thereby compensated so that the constricted portion 19 temporarily disappears (FIGURE 3 f), the magnetic bottle of the chamber for the production of high temperatures is opened and the plasma 22 is injected therein. Thus, the system of elements 5, 6 and 7 operates in the manner of a magnetic shutter of which the release permits the momentary injection into the left chamber of the plasma previously compressed within the right chamber of FIGURE 1. 7

Once the pulse 25 is terminated, the constriction 19' reappears (FIGURE 33) and the plasma is thereupon enclosed within the magnetic bottle of the chamber for the production of high temperatures comprised between the constrictions 18 and 19. The plasma, therefore, re-

; mains under the effect of compression of this bottle during a certain time during which the temperature thereofincreases, and eventually may lead to a thermonuclear reaction. Thereafter, the burnt-up particles are evacuated bythe'pump 2, the systemreturns to the condition of' FIGURE 3a, and the cycle recommences.

While I have shown and described one embodiment in accordance with the present invention,'it is understood that the same is not limited thereto but is susceptible of many changes and modifications within the spirit and scope of the presentinvention and I therefore,.do not wish 'to be limited to the specific details shown and described herein but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims.

I claim: p

1. In a plasma-confining device, an evacuated vessel comprising a high temperature production chamber and a plasma injection chamber, means for establishing in said high temperature production chamber a magnetic field having lines o'f'force extending substantially along said chamber between both extremities thereof to effectively confine plasma particles'to be injected therein, magnetic mirror means at both said extremities to prevent escapement of said particles from said chamber, said injection chamber being defined between one of said magnetic mirror means and one extremity of said vessel, means for injecting ions and electrons for forming plasma into The source 16 thereupon transmits mirror means after the compression of said plasma to thereby inject said compressed plasma into said high temperature production chamber.

2. A device as claimed in claim 1, wherein said magnetic shutter means includes a magnetic coil producing, upon energization thereof, a magnetic field opposite said one magnetic mirror field, and means including a pulse generator and connecting means from said generator to said coil for periodically sending an electric pulse through said coil.

3. A device as claimed in claim 1, further comprising means for establishing in said plasma injection chamber a magnetic field having lines of force extending substantially along said chamber between said one magnetic mirror means and said one extremity of said vessel, and wherein said magnetic piston means is formed by a delay line extending along said injection chamber, and means including a pulse generator and a connection from said pulse generator to the said delay line adjacent said one vessel extremity for periodically sending through said line w an electric pulse propagating therealong towards said one magnetic mirror means and thereby eiiectively forming a magnetic mirror movable along said injection chamber.

4. A device as claimed in claim 1, further comprising timing means for controlling said ion and electron injecting means, said magnetic piston means and said mag 5 netie shutter means to thereby produce a periodic sequence of operation consisting of initially injecting the ion and electron particles, then eliecting plasma compression by said magnetic piston means, and finally operating said magnetic shutter means.

References Cited in the file of this patent UNITED STATES PATENTS 2,868,991 Josephson Jan. 13, 1959 2,927,232 Luce Mar. 1, 1960 2,933,611 Foster Apr. 19, 1960 2,940,011 Kolb June 7, 1960 2,946,914 Colgate et al July 26, 1960 2,969,308 Bell et a1 Jan. 24, 1961 OTHER REFERENCES Proceedings of the Second United Nations International Conference on the Peaceful Uses of Atomic Energy, held in Geneva Sept. l-Sept. 13, 1958, vol. 32, United Nations Geneva 1958, pp. 256-265.

An Introduction to Thermonuclear Research, Albert Simon, Pergamon Press, N.Y., 1959 Scientific Library, date Oct. 10, 1959, pp. 92-94.

Project Sherwood, by Amasa S. Bishop, Addison Wesley Pub. Co., Reading, Mass., September 1958, pp. 136- 138, 143-151, pages 122126. 

1. IN A PLASMA-CONFINING DEVICE, AN EVACUATED VESSEL COMPRISING A HIGH TEMPERATURE PRODUCTION CHAMBER AND A PLASMA INJECTION CHAMBER, MEANS FOR ESTABLISHING IN SAID HIGH TEMPERATURE PRODUCTION CHAMBER A MAGNETIC FIELD HAVING LINES OF FORCE EXTENDING SUBSTANTIALLY ALONG SAID CHAMBER BETWEEN BOTH EXTREMITIES THEREOF TO EFFECTIVELY CONFINE PLASMA PARTICLES TO BE INJECTED THEREIN, MAGNETIC MIRROR MEANS AT BOTH SAID EXTREMITIES TO PREVENT ESCAPEMENT OF SAID PARTICLES FROM SAID CHAMBER, SAID INJECTION CHAMBER BEING DEFINED BETWEEN ONE OF SAID MAGNETIC MIRROR MEANS AND ONE EXTREMITY OF SAID VESSEL, MEANS 